Monolayer cultures of established tumor cell lines are frequently used in basic tumor biology research and anti-tumor drug development. However, a two-dimensional, flat culture model insufficiently reflects the three-dimensional (3D) tumor architecture. Therefore, specific aspects related to the in vivo development of solute diffusion gradients can only be studied in a three-dimensional culture system like for instance the multicellular tumor spheroid or aggregate model. Tumor spheroids or aggregates mimic avascular tumor regions, characterized by limited nutrient supply due to diffusion barriers through multicellular layers.
However, the widespread use of 3D cultures in research is limited by inconvenient generation and handling. Therefore, a simple and rapid method was developed to generate single spheroids or aggregates in suspension culture in a high-throughput fashion. Single spheroids or aggregates with equal sizes and homogenous spherical geometry can be generated in single wells of a 96-well plate within a 24 hour culture period. It is a standardized culture format with easy access for compound handling and spheroid harvest for subsequent analysis. The uniform size and geometry guarantees the development of almost identical diffusion gradients in each spheroid or aggregate (Ivascu, A. and Kubbies, M., J. Biomol. Screening 11 (2006) 922-932). The known spheroid generation protocol includes the addition of a murine basement membrane extract (rBM), a mixture of extracellular matrix proteins that induces a compaction of the aggregate to a spheroid.
Inami, K., et al. report antitumor activity of anti-C-ERC/mesothelin monoclonal antibody in vivo (Cancer Sci. 101 (2010) 969-974).